Molecules with which functional groups may form polymers via dehydration reactions? a)carbonyl groups |
e)either hydroxyl or carboxyl groups |
Which of these molecules is not formed by dehydration reactions? a)disaccharides |
fatty acids |
Which of these classes of biological molecules consist of both small molecules and macromolecular polymers? a)nucleic acids |
carbohydrates |
Which of the following is not a polymer? a)starch |
glucose |
What is the chemical reaction mechanism by which cells make polymers from monomers? a)dehydration reactions |
dehydration reactions |
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? 12 |
10 |
Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement? DNA |
a steroid |
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? a)Dehydration reactions can occur only after hydrolysis. b)Hydrolysis creates monomers, and dehydration reactions break down polymers. c)Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. d)Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. e)Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. |
d)Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. |
Polysaccharides, triacylglycerides, and proteins are similar in that they a)are decomposed into their subunits by dehydration reactions. b)are synthesized from monomers by the process of hydrolysis. c)are synthesized from subunits by dehydration reactions. d)are synthesized as a result of peptide bond formation between monomers. e)all contain nitrogen in their monomer building blocks |
c)are synthesized from subunits by dehydration reactions. |
Dehydration reactions are used in forming which of the following compounds? a)triacylglycerides |
triacylglycerides, polysaccharides, and proteins |
DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase? a)The phosphodiester bonds between deoxyribose sugars would be broken. b)All bases would be separated from the deoxyribose sugars. c)The two strands of the double helix would separate. d)The pyrimidines would be separated from the deoxyribose sugars. e)The purines would be separated from the deoxyribose sugars. |
The phosphodiester bonds between deoxyribose sugars would be broken. |
Which of the following polymers contain nitrogen? a)glycogen |
chitin |
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? a) C18H32O16 |
a) C18H32O16 |
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? a)cellulose |
starch |
On food packages, to what does the term insoluble fiber refer? a)amylopectin |
cellulose |
A molecule with the chemical formula is probably a a)carbohydrate. |
carbohydrate and monosaccharide only. |
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? a)as a hexose |
as a disaccharide |
All of the following are polysaccharides except a)chitin. |
lactose |
Which of the following is true of both starch and cellulose? a)They are both polymers of glucose. |
They are both polymers of glucose. |
Which of the following is true of cellulose? a)It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy in plant cells, it is digestible by bacteria in the human gut, and it is a major structural component of plant cell walls. b)It is a storage polysaccharide for energy in plant cells. c)It is a major structural component of plant cell walls. d)It is digestible by bacteria in the human gut. e)It is a polymer composed of enantiomers of glucose |
It is a major structural component of plant cell walls. |
Humans can digest starch but not cellulose because a)the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group. b)humans harbor starch-digesting bacteria in the digestive tract. c)the monomer of starch is glucose, while the monomer of cellulose is galactose. d)humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. e)humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose |
humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. |
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA a)is a six-carbon sugar and the sugar in RNA is a five-carbon sugar. b)contains one less oxygen atom. c)is in the α configuration and the sugar in RNA is in the β configuration. d)is an aldehyde sugar and the sugar in RNA is a keto sugar. e)can form a double-stranded molecule |
contains one less oxygen atom. |
If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled? a)phospholipids |
both phospholipids and nucleic acids |
How will brief heating (to 95°C) affect macromolecular structures in aqueous solution? a)Starch will hydrolyze into monomeric sugars. b)DNA duplexes will unwind and separate. c)Proteins will unfold (denature). d)DNA duplexes will unwind and separate, and proteins will unfold (denature). e)Proteins will hydrolyze into amino acids |
DNA duplexes will unwind and separate, and proteins will unfold (denature). |
If cells are grown in a medium containing radioactive 15N, which of these molecules will be labeled? a)both proteins and nucleic acids |
both proteins and nucleic acids |
Which of the following is not a monomer/polymer pairing? a)deoxyribonucleotide/DNA |
triglyceride/phospholipid bilayer |
Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides. Among these biological polymers, which has the least structural variety? proteins |
DNA |
Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides. Which class of biological polymer has the greatest functional variety? a)proteins |
proteins |
Use the following information to answer the question below. Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides. Professor Jamey Marth at the University of California, Santa Barbara, identified 70 molecules that are used to build cellular macromolecules and structures. These include at least 34 saccharides, 8 nucleosides, and 20 amino acids. In theory, then, which class of biological polymer has the greatest information-coding capacity? polysaccharides |
polysaccharides |
Which of the following statements concerning saturated fats is not true? a)They are one of several factors that contribute to atherosclerosis. b)They generally solidify at room temperature. c)They are more common in animals than in plants. d)They contain more hydrogen than unsaturated fats having the same number of carbon atoms. e)They have multiple double bonds in the carbon chains of their fatty acids |
They have multiple double bonds in the carbon chains of their fatty acids |
A molecule with the formula is C18H36O2 probably a nucleic acid. |
fatty acid |
Which of the following statements is true for the class of biological molecules known as lipids? a)They are made from glycerol, fatty acids, and phosphate. b)They are made by dehydration reactions. c)They contain nitrogen. d)They contain less energy than proteins and carbohydrates. e)They are insoluble in water. |
They are insoluble in water. |
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil? a)The hydrogenated vegetable oil is less likely to clog arteries. b)The hydrogenated vegetable oil stays solid at room temperature. c)The hydrogenated vegetable oil has a lower melting point. d)The hydrogenated vegetable oil has more "kinks" in the fatty acid chains. e)The hydrogenated vegetable oil has fewer trans fatty acids. |
The hydrogenated vegetable oil stays solid at room temperature. |
Which of the following is true regarding saturated fatty acids? a)They are usually produced by plants. b)They are the principal molecules in lard and butter. c)They are the predominant fatty acid in corn oil. d)They are usually liquid at room temperature. e)They have double bonds between carbon atoms of the fatty acids. |
They are the principal molecules in lard and butter |
Why are human sex hormones considered to be lipids? a)They are hydrophilic compounds. |
They are not soluble in water. |
All of the following contain amino acids except a)insulin. |
cholesterol |
The bonding of two amino acid molecules to form a larger molecule requires a)the release of a water molecule. |
the release of a water molecule. |
There are 20 different amino acids. What makes one amino acid different from another? a)different side chains (R groups) attached to a carboxyl carbon b)different asymmetric carbons c)different side chains (R groups) attached to an α carbon d)different side chains (R groups) attached to the amino groups e)different structural and optical isomers |
different side chains (R groups) attached to an α carbon |
Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein? 101 |
99 |
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
12^20 |
20^12 |
Which bonds are created during the formation of the primary structure of a protein? a)phosphodiester bonds |
peptide bonds |
What maintains the secondary structure of a protein? a)disulfide bonds |
hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond |
Which level of protein structure do the α helix and the β pleated sheet represent? a)primary |
secondary |
Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins? a)ionic bonds |
hydrogen bonds |
The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by a)ionic bonds. |
hydrogen bonds |
The tertiary structure of a protein is the a)order in which amino acids are joined in a polypeptide chain. b)overall protein structure resulting from the aggregation of two or more polypeptide subunits. c)bonding together of several polypeptide chains by weak bonds. d)organization of a polypeptide chain into an α helix or β pleated sheet. e)unique three-dimensional shape of the fully folded polypeptide. |
unique three-dimensional shape of the fully folded polypeptide |
What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide’s specific three-dimensional shape? a)disulfide bond |
disulfide bond |
At which level of protein structure are interactions between the side chains (R groups) most important? a)primary |
tertiary |
The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid leucine is -CH2-CH(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution? a)Leucine would be in the interior, and serine would be on the exterior of the globular protein. b)Both serine and leucine would be in the interior and on the exterior of the globular protein. c)Serine would be in the interior, and leucine would be on the exterior of the globular protein. d)Both serine and leucine would be in the interior of the globular protein. e)Both serine and leucine would be on the exterior of the globular protein. |
Leucine would be in the interior, and serine would be on the exterior of the globular protein. |
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides? a)Alzheimer’s and Parkinson’s only |
Alzheimer’s and Parkinson’s only |
Changing a single amino acid in a protein consisting of 325 amino acids would a)always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity. b)always alter the primary structure of the protein and disrupt its biological activity. c)alter the primary structure of the protein but not its tertiary structure or function. d)cause the tertiary structure of the protein to unfold. e)always alter the biological activity or function of the protein. |
always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity |
Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits a)altered primary structure. |
altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered. |
In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine? a)anywhere in the protein, with equal probability b)in the interior of the folded protein, away from water c)in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains d)on the exterior surface of the protein, interacting with water e)in the transmembrane portion interacting with lipid fatty acid chains |
in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains |
Which of the following techniques uses the amino acid sequences of polypeptides to predict a protein’s three-dimensional structure?
a)X-ray crystallography |
bioinformatics |
If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled? a)both proteins and nucleic acids |
proteins |
What is the term used for a protein molecule that assists in the proper folding of other proteins? a)denaturing protein |
chaperonin |
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism a)is more closely related to rats than to frogs. b)is more closely related to frogs than to humans c)is more closely related to humans than to rats. d)is more closely related to humans than to frogs. e)is more closely related to gibbons than to rats. |
is more closely related to frogs than to humans |
Which of the following statements about the 5′ end of a polynucleotide strand of DNA is correct? a)The 5′ end is the fifth position on one of the nitrogenous bases. b)The 5′ end has a carboxyl group attached to the number 5 carbon of deoxyribose. c)The 5′ end has a phosphate group attached to the number 5 carbon of deoxyribose. d)The 5′ end has a phosphate group attached to the number 5 carbon of the nitrogenous base. e)The 5′ end has a hydroxyl group attached to the number 5 carbon of deoxyribose. |
The 5′ end has a phosphate group attached to the number 5 carbon of deoxyribose. |
One of the primary functions of RNA molecules is to a)act as a pattern or blueprint to form DNA. b)form the genes of higher organisms. c)transmit genetic information to offspring. d)function in the synthesis of proteins. e)make a copy of itself, thus ensuring genetic continuity. |
function in the synthesis of proteins. |
If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled? a)phospholipids |
RNA |
Which of the following descriptions best fits the class of molecules known as nucleotides? a)a nitrogenous base and a pentose sugar b)a pentose sugar and a purine or pyrimidine c)a nitrogenous base and a phosphate group d)a nitrogenous base, a phosphate group, and a pentose sugar e)a phosphate group and an adenine or uracil |
a nitrogenous base, a phosphate group, and a pentose sugar |
Which of the following are nitrogenous bases of the pyrimidine type? a)ribose and deoxyribose |
cytosine and uracil |
Which of the following are nitrogenous bases of the purine type? a)thymine and uracil |
guanine and adenine |
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? 10 |
40 |
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of a)120 adenine and 120 cytosine molecules. |
120 thymine and 120 adenine molecules. |
Which of the following statements best summarizes the differences between DNA and RNA? a)DNA encodes hereditary information, whereas RNA does not. b)The bases in DNA form base-paired duplexes, whereas the bases in RNA do not. c)DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides. d)DNA contains the base uracil, whereas RNA contains the base thymine. e)DNA nucleotides contain a different sugar than RNA nucleotides. |
DNA nucleotides contain a different sugar than RNA nucleotides. |
What is the structural feature that allows DNA to replicate? a)complementary pairing of the nitrogenous bases b)disulfide bonding (bridging) of the two helixes c)sugar-phosphate backbone d)three-component structure of the nucleotides e)twisting of the molecule to form an α helix |
complementary pairing of the nitrogenous bases |
If one strand of a DNA molecule has the sequence of bases 5’ATTGCA3′, the other complementary strand would have the sequence a)3’UAACGU5′. |
5’TGCAAT3′. |
Bio Chap 5
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